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<head><meta charset="utf-8"><title>I-prioritize #80207 `!Sized` return type error panics with … · t-compiler/wg-prioritization/alerts · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/index.html">t-compiler/wg-prioritization/alerts</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html">I-prioritize #80207 `!Sized` return type error panics with …</a></h3>

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<a name="220494910"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220494910" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220494910">(Dec 20 2020 at 00:30)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="3111">@WG-prioritization/alerts</span> issue <a href="https://github.com/rust-lang/rust/issues/80207">#80207</a> has been requested for prioritization.</p>
<h1><a href="https://forge.rust-lang.org/compiler/prioritization/procedure.html#assign-priority-to-unprioritized-issues-with-i-prioritize-label">Procedure</a></h1>
<ul>
<li>Priority?</li>
<li>Regression?</li>
<li>Notify people/groups?</li>
<li>Needs <code>I-nominated</code>?</li>
</ul>



<a name="220495351"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220495351" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220495351">(Dec 20 2020 at 00:45)</a>:</h4>
<p>I feel quite confused by this one; why did the code used to compile even though the return type was unsized? It seems like the code shouldn't compile, though it definitely shouldn't be ICEing.</p>



<a name="220495352"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220495352" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220495352">(Dec 20 2020 at 00:45)</a>:</h4>
<p>Anyway, maybe P-high.</p>



<a name="220510171"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220510171" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220510171">(Dec 20 2020 at 08:54)</a>:</h4>
<p>The code used to compile because of the <code>Self: Sized</code> bound</p>



<a name="220510176"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220510176" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220510176">(Dec 20 2020 at 08:54)</a>:</h4>
<p>so it was "just" uncallable as <code>dyn Trait</code> is never sized</p>



<a name="220510179"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220510179" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220510179">(Dec 20 2020 at 08:55)</a>:</h4>
<p>consider that you were actually unable to use that impl <code>P-high</code> seems fine to me even though it is a regression</p>



<a name="220537492"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220537492" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220537492">(Dec 20 2020 at 21:07)</a>:</h4>
<p>Ah, I see: the impl wouldn't cause an error, but any call to the method would.</p>



<a name="220537544"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2380207%20%60%21Sized%60%20return%20type%20error%20panics%20with%20%E2%80%A6/near/220537544" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2380207.20.60!Sized.60.20return.20type.20error.20panics.20with.20.E2.80.A6.html#220537544">(Dec 20 2020 at 21:08)</a>:</h4>
<p>Issue <a href="https://github.com/rust-lang/rust/issues/80207">#80207</a>'s prioritization request has been removed.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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